The present invention relates to wireless communication systems and, more particularly, to an apparatus and method for establishing a wireless communication network.
Since the success of the Ethernet project in the 1970's, the advantages of digital computing networks have become increasingly apparent. While wired networks have demonstrated the computing advantages of networks, the mobility limitations imposed by the infrastructure of wired networks has motivated the development of wireless local area networks (LANs). Unfettered by conventional wired network connections, wireless network users can move about almost without restriction and access the network from almost anywhere within range of the wireless transceiver. A wireless network may also be more economical than a wired network because of the high cost and difficultly of wiring or rewiring existing structures to connect network nodes when expanding or altering the network. Further, wireless networks offer flexibility that cannot be matched by their wired network counterparts. For example, wireless communication facilitates the creation and termination of transient or ad hoc networks permitting a plurality of mobile data processing devices to establish communication for a purpose and then terminate the communication links at the conclusion of the task. For instance, a group of employees meeting to discuss future product designs or plans can use portable data processing devices to create a wireless network for sharing data and then disband the network when the meeting ends. Similarly, a mobile telephone might be used to establish a temporary wireless network with a vending machine to facilitate electronic payment for a purchase.
Generally, a wireless network may have an infrastructure configuration or an ad hoc configuration. In an ad hoc network, data processing units are brought together “on the fly” so there is no fixed points or structure to the network and, typically, every node is able to communicate with every other node. Algorithms, such as the spokesperson election algorithm, have been designed to elect one of the data processing devices as the base station or “master” controlling operation of the network with remaining devices or nodes being designated as “slaves.” Another ad hoc network architecture uses a broadcasting and flooding method to establish a structure for the nodes. On the other hand, the wireless network may have an infrastructure with fixed network access points with which the wireless slave nodes communicate. These network access points may be connected to land lines to bridge the wireless nodes to nodes of other networks, such as the Internet, to broaden the wireless network's scope and capability.
While wireless communication has numerous advantages, the transient nature of wireless networks and the fact that the bounds of the network are limited only by the strength of the radio signal used for communication presents unique problems, particularly when used for a localized network. There is no wiring to define membership in the wireless network and no physical method of preventing a device within radio range from joining the network. For example, when two devices conforming to the Bluetooth wireless communication standard come within radio range of each other, an electronic conversation is automatically initiated to determine whether there is data to be shared and whether one of the devices needs to control the other. Once the conversation has taken place, the communicating devices can automatically form a network known as a personal area network or piconet and initiate data transfer. Bluetooth devices transmit a one milliwatt signal that limits the range to approximately ten meters, reducing the chances of interference between the Bluetooth device and other electronic devices such as portable telephones or television.
However, even with low power, the radio frequency signals used for network communications can penetrate the walls of a structure. While this may make the signal useful for controlling devices located in different rooms or even different buildings, the ability of radio frequency signals to penetrate the walls of a structure also makes it difficult to limit geographic extent of and access to a wireless network and control interference from other nearby wireless communication devices. Wireless networking, more than any other network technology, requires an access control mechanism.
What is desired, therefore, is a system that facilitates the establishment of reliable, localized wireless communication networks having controlled access.